﻿using System;
using System.Diagnostics;
using Windows.ApplicationModel;
using Windows.ApplicationModel.Activation;
using Windows.UI.Core;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Navigation;

namespace douban.app
{
    /// <summary>
    /// 提供特定于应用程序的行为，以补充默认的应用程序类。
    /// </summary>
    sealed partial class App : Application
    {
        /// <summary>
        /// 初始化单一实例应用程序对象。这是执行的创作代码的第一行，
        /// 已执行，逻辑上等同于 main() 或 WinMain()。
        /// </summary>
        public App()
        {
            Microsoft.ApplicationInsights.WindowsAppInitializer.InitializeAsync(
                Microsoft.ApplicationInsights.WindowsCollectors.Metadata |
                Microsoft.ApplicationInsights.WindowsCollectors.Session);
            this.InitializeComponent();
            this.Suspending += OnSuspending;

           

        }

        /// <summary>
        /// 在应用程序由最终用户正常启动时进行调用。
        /// 将在启动应用程序以打开特定文件等情况下使用。
        /// </summary>
        /// <param name="e">有关启动请求和过程的详细信息。</param>
        protected override void OnLaunched(LaunchActivatedEventArgs e)
        {

#if DEBUG
            //if (System.Diagnostics.Debugger.IsAttached)
            //{
            //    this.DebugSettings.EnableFrameRateCounter = true;
            //}
#endif

         

            Frame rootFrame = Window.Current.Content as Frame;

            // 不要在窗口已包含内容时重复应用程序初始化，
            // 只需确保窗口处于活动状态
            if (rootFrame == null)
            {
                // 创建要充当导航上下文的框架，并导航到第一页
                rootFrame = new Frame();

                rootFrame.NavigationFailed += OnNavigationFailed;
                rootFrame.Navigated += OnNavigated;

                //foreach (var item in Windows.Globalization.ApplicationLanguages.Languages)
                //{
                //    Debug.WriteLine(item);
                //}

                rootFrame.Language = "zh-CN";

                if (e.PreviousExecutionState == ApplicationExecutionState.Terminated)
                {
                    //TODO: 从之前挂起的应用程序加载状态

                }

                // 将框架放在当前窗口中
                Window.Current.Content = rootFrame;
            }

            if (rootFrame.Content == null)
            {
                // 当导航堆栈尚未还原时，导航到第一页，
                // 并通过将所需信息作为导航参数传入来配置
                // 参数
                rootFrame.Navigate(typeof (Views.MainPage), e.Arguments);
            }
            // 确保当前窗口处于活动状态
            Window.Current.Activate();


            // Register a handler for BackRequested events and set the
            // visibility of the Back button
            SystemNavigationManager.GetForCurrentView().BackRequested += OnBackRequested;
            SystemNavigationManager.GetForCurrentView().AppViewBackButtonVisibility =
           rootFrame.CanGoBack ?
           AppViewBackButtonVisibility.Visible :
           AppViewBackButtonVisibility.Collapsed;
        }

        /// <summary>
        /// 导航到特定页失败时调用
        /// </summary>
        ///<param name="sender">导航失败的框架</param>
        ///<param name="e">有关导航失败的详细信息</param>
        void OnNavigationFailed(object sender, NavigationFailedEventArgs e)
        {
            throw new Exception("Failed to load Page " + e.SourcePageType.FullName);
        }

        /// <summary>
        /// 在将要挂起应用程序执行时调用。  在不知道应用程序
        /// 无需知道应用程序会被终止还是会恢复，
        /// 并让内存内容保持不变。
        /// </summary>
        /// <param name="sender">挂起的请求的源。</param>
        /// <param name="e">有关挂起请求的详细信息。</param>
        private void OnSuspending(object sender, SuspendingEventArgs e)
        {
            var deferral = e.SuspendingOperation.GetDeferral();
            //TODO: 保存应用程序状态并停止任何后台活动
            deferral.Complete();
        }


        private void OnNavigated(object sender, NavigationEventArgs e)
        {
            // Each time a navigation event occurs, update the Back button's visibility
            SystemNavigationManager.GetForCurrentView().AppViewBackButtonVisibility =
                ((Frame)sender).CanGoBack ?AppViewBackButtonVisibility.Visible :AppViewBackButtonVisibility.Collapsed;
        }


        private void OnBackRequested(object sender, BackRequestedEventArgs e)
        {
            Frame rootFrame = Window.Current.Content as Frame;

            if (rootFrame!= null&& rootFrame.CanGoBack)
            {
                e.Handled = true;
                rootFrame.GoBack();
            }
        }
    }
}
